Method of operating a gas turbine

Abstract

In a gas turbine having a plurality of hybrid burners, each of which has a pilot burner and a main burner, a different pilot fuel quantity is fed to the pilot burners as a function of the load on the gas turbine. This provides both stable operation of the gas turbine at low loads and effective suppression of combustion oscillations at high loads.

We claim:  
     
       1. A method of operating a turbine, which comprises the steps of: 
       providing a gas turbine having a plurality of hybrid burners disposed in a combustion chamber, each of the hybrid burners having a pilot burner and a main burner, and a pilot fuel quantity being supplied to the pilot burner; and  
       operating at least two of the pilot burners with a different pilot fuel quantity, a difference in the pilot fuel quantity being set in dependence on a load of the gas turbine.  
     
     
       2. The method according to  claim 1 , which comprises setting the difference in the pilot fuel quantity to increase with an increasing load. 
     
     
       3. The method according to  claim 1 , which comprises during a maximum load of the gas turbine, operating a major proportion of the hybrid burners between one and two percent of a maximum pilot fuel quantity and a remainder of the hybrid burners are operated with between five and 15 percent of the maximum pilot fuel quantity. 
     
     
       4. The method according to  claim 1 , which comprises during loads above 60% of a maximum load on the gas turbine, operating a first number of the hybrid burners with a first pilot fuel quantity and operating a second number of the hybrid burners with a second pilot fuel quantity, the first number being more than four times as large as the second number and the second pilot fuel quantity being more than two times as large as the first pilot fuel quantity. 
     
     
       5. The method according to  claim 1 , which comprises providing the combustion chamber of the gas turbine as an annular combustion chamber.